Patents by Inventor Christopher A. Gresham

Christopher A. Gresham has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8695443
    Abstract: An integrated apparatus and method for screening an object for a target material is provided. The integrated apparatus comprises a housing and an integrated screener. The housing is positionable adjacent the object, and has a channel therethrough. The integrated screener is positionable in the housing, and comprises a fan, at least one filter, a heater and an analyzer. The fan is for drawing air carrying particles and vapor through the channel of the housing. The filter(s) is/are positionable in the channel of the housing for passage of the air therethrough. The filter(s) comprise(s) at least one metal foam having a plurality of pores therein for collecting and adsorbing a sample from the particles and vapor passing therethrough. The heater is for applying heat to the at least one metal foam whereby the collected sample is desorbed from the metal foam. The analyzer detects the target material from the desorbed sample.
    Type: Grant
    Filed: August 30, 2010
    Date of Patent: April 15, 2014
    Assignee: Sandia Corporation
    Inventors: David A. Jones, Christopher A. Gresham, Marc L. Basiliere, James J. Spates, Philip J. Rodacy
  • Patent number: 7403065
    Abstract: A differential transimpedance amplifier circuit for correlated differential amplification. The amplifier circuit increase electronic signal-to-noise ratios in charge detection circuits designed for the detection of very small quantities of electrical charge and/or very weak electromagnetic waves. A differential, integrating capacitive transimpedance amplifier integrated circuit comprising capacitor feedback loops performs time-correlated subtraction of noise.
    Type: Grant
    Filed: August 22, 2006
    Date of Patent: July 22, 2008
    Assignees: Sandia Corporation, Arizona Board of Regents
    Inventors: Christopher A. Gresham, M. Bonner Denton, Roger P. Sperline
  • Patent number: 6809313
    Abstract: An ion mobility spectrometer includes a drift tube having a collecting surface covering a collecting area at one end of the tube. The surface comprises a plurality of closely spaced conductive elements on a non-conductive substrate, each conductive element being electrically insulated from each other element. A plurality of capacitive transimpedance amplifiers (CTIA) adjacent the collecting surface are electrically connected to the plurality of elements, so charge from an ion striking an element is transferred to the capacitor of the connected CTIA. A controller counts the charge on the capacitors over a period of time.
    Type: Grant
    Filed: March 17, 2003
    Date of Patent: October 26, 2004
    Assignee: Sandia Corporation
    Inventors: Christopher A. Gresham, Phillip J. Rodacy, M. Bonner Denton, Roger Sperline